At the current point in time, its kind of hard for an Alliance to actually try to plan events that people may be interested in doing, especially for alliances that existed prior to NGS. A schedule or calendar would go a long way towards at least enabling groups to plan ahead and maintain interesting in playing the game.
In Base PSO2, while it was still the main game, having an UQ Calendar was really convenient and nice - it was actually possible to have alliances plan around doing specific content (e.g. Ep4 Yamato + 4-player, Mother, Deus + 4-player, Ep5 Omega Persona, Ep6 Face of Abyss, Twisted with Hatred). Aside from UQ's, players could plan to do Busters, Divide Quests, Ultimate Quests, Extreme Quest (particularly 4) or Trigger Quests, so the UQ Calendar allowed people to hit whatever UQ was set for making progress on content and gear and outside of the UQ, there was still other content to fall back on.
In Current NGS, the current set of content to do is essentially only 3 pieces, 2 of which are on an unpredictable schedule: Combat Sector Farm Gigantix Urgent Quests
Quite literally, the only activity an alliance can actively plan around in NGS is going to a combat sector. I don't mean to be rude, but there really is only so much time you can spend running around each sector before you want a change of pace that isn't combat sector.
Gigantix are reliant on RNG for having a storm occur, and its very possible to wait an entire hour and get 0 storms. It feels especially bad to watch your food buff and mag buff expire barely seeing any Gigas. People may have varied opinions on what Gigas should be, but a fact of the matter is that it is one of the few prominent things to do, so it would be nice to be able to gather the crew and go after them. Unfortunately, this currently means sitting around and waiting for a storm.
An Urgent Quest has a 15 minute lead time which means there really is no way to plan around it. A group of people can't aim for going to a UQ that is set to occur at 10 PM because we have no way of knowing a UQ will occur at 10 PM unless it is 9:45 PM and we get an alert, for which most people are getting from a 3rd-party discord if they are not online in NGS (since the official NGS discord does not provide any alert information of what is going on in-game).
So essentially, 2/3 of the content we have to play with is kinda locked into a random schedule that we have no clue about and no ability to plan around. I'm not saying there is enough content, but the fact is the little content we do have, we don't have even a semi-reliable way of attempting to go after.
Fundamentally, I believe having a schedule would at least allow players to attempt to reinvigorate alliances by providing them methods to actually plan activities. It also means players won't have to sit around in their field of choice alt-tabbed out waiting for Gigas to appears. Exploration sectors aren't combat sectors so you kinda don't have much you can do aside from farm relatively sparse groups of enemies assuming you haven't already collected your materials. Similarly, it means people going after Combat Sector farm can try to aim for a time when PSE's would be expected to occur more often.
Similarly, it would be nice to have a UQ schedule for old PSO2 for much of the same reason - there are still people interested in attempting to tackle Twisted with Hatred for example. Similarly, if seasonal UQ's are added into rotation, it would be nice to be able to go after them to experience UQ's that we may never have seen before, if only at least once or twice. Fact is that realistically, there is really no opportunity for someone to come into or go back to PSO2 and try to tackle the hardest UQ the game has to offer because it occurs so infrequently and only appears randomly. It would also be pretty cool if Cradle of Darkness and Drawn to Darkness weren't in the UQ pool. I understand that the lack of an old UQ schedule is intentional, but it would be real nice to have one.
Its just real painful to watch your alliance become more and more inactive because you can't plan around any of the content and people became tired of grinding combat sectors. I don't really expect much to change on that front, but at least having a calendar or schedule means some attempt can be made to see if people still want to play together. I just don't see how I can ask people to AFK with me together in an exploration sector and have that work as a regularly planned alliance activity.